<template>
  <div class="app-container">
    <h2 style="text-align: center;">发布新课程</h2>
    <el-steps :active="1" process-status="wait" align-center style="margin-bottom: 40px;">
      <el-step title="编辑课程基本信息"/>
      <el-step title="编辑课程大纲"/>
      <el-step title="发布课程"/>
    </el-steps>

    <el-form label-width="120px">
    <el-form-item label="课程标题">
        <el-input v-model="courseInfo.title" placeholder=" 示例：机器学习项目课：从基础到搭建项目视频课程。专业名称注意大小写"/>
    </el-form-item>

    <el-form-item label="课程分类">
        <el-select
            v-model="courseInfo.subjectParentId"
            placeholder="一级分类" @change="subjectLevelOneChanged">
            <el-option
                v-for="subject in subjectOneList"
                :key="subject.id"
                :label="subject.title"
                :value="subject.id"/>
        </el-select>

        <el-select v-model="courseInfo.subjectId" placeholder="二级分类">
            <el-option
                v-for="subject in subjectTwoList"
                :key="subject.id"
                :label="subject.title"
                :value="subject.id"/>
        </el-select>
    </el-form-item>

    
    <el-form-item label="课程讲师">
        <el-select
            v-model="courseInfo.teacherId"
            placeholder="请选择">
            <el-option
                v-for="teacher in teacherList"
                :key="teacher.id"
                :label="teacher.name"
                :value="teacher.id"/>
        </el-select>
    </el-form-item>

    <el-form-item label="总课时">
        <el-input-number :min="0" v-model="courseInfo.lessonNum" controls-position="right" placeholder="请填写课程的总课时数"/>
    </el-form-item>

    <el-form-item label="课程简介">
        <tinymce :height="300" v-model="courseInfo.description"/>
    </el-form-item>

    <el-form-item label="课程封面">
        <el-upload
            :show-file-list="false"
            :on-success="handleAvatarSuccess"
            :before-upload="beforeAvatarUpload"
            :action="BASE_API+'/eduoss/fileoss'"
            class="avatar-uploader">
            <img :src="courseInfo.cover">
        </el-upload>
    </el-form-item>

    <el-form-item label="课程价格">
        <el-input-number :min="0" v-model="courseInfo.price" controls-position="right" placeholder="免费课程请设置为0元"/> 元
    </el-form-item>
    <el-form-item>
        <el-button :disabled="saveBtnDisabled" type="primary" @click="saveOrUpdate">下一步</el-button>
    </el-form-item>
    </el-form>
  </div>
</template>
<script>
import course from '@/api/edu/course'
import subject from '@/api/edu/subject'
import Tinymce from '@/components/Tinymce'

export default{
  components: { Tinymce },
  data(){
    return{
      //保存按钮是否禁用
      saveBtnDisabled: false,
      courseInfo:{
        title: '',
        subjectId: '',//二级分类
        subjectParentId:'',//一级分类
        teacherId: '',
        lessonNum: 0,
        description: '',
        cover: '/static/蜡笔小新.jpg',
        price: 0
      },
      courseId:'',
      //讲师列表
      teacherList:[],
      //一级分类列表
      subjectOneList:[],
      //二级分类列表
      subjectTwoList:[],
      BASE_API: process.env.BASE_API // 接口API地址
    }
  },
  created(){
      //判断是否有id值
      if (this.$route.params && this.$route.params.id)
      {
        this.courseId = this.$route.params.id
        this.getInfo()
      }
      else{
            this.getTeacherList()
            this.getOneSubject()
      }
      
  },
  methods:{
    //根据id查询课程信息
    getInfo(){
        course.getCourseInfoById(this.courseId)
            .then(response => {
                this.courseInfo = response.data.courseInfoVo
                //查询所有分类
                subject.getSubjectList()
                    .then(response => {
                        this.subjectOneList = response.data.list
                        //遍历一级分类
                        for (let i=0;i<this.subjectOneList.length;i++)
                        {
                            let curOneSubject = this.subjectOneList[i]
                            //比较一级分类
                            if (this.courseInfo.subjectParentId == curOneSubject.id)
                            {
                                //获取一级分类里的二级分类
                                this.subjectTwoList = curOneSubject.children
                            }
                        }
                    })
            })
    },
    //封面上传成功
    handleAvatarSuccess(res,file){
        this.courseInfo.cover = res.data.url
    },
    //封面上传之前
    beforeAvatarUpload(file){
        const isJPG = file.type === 'image/jpeg'
        const isLt2M = file.size / 1024 / 1024 < 2
        if (!isJPG) {
            this.$message.error('上传头像图片只能是 JPG 格式!')
        }
        if (!isLt2M) {
            this.$message.error('上传头像图片大小不能超过 2MB!')
        }
        return isJPG && isLt2M
    },
    //点击一级分类显示二级分类
    subjectLevelOneChanged(value){
        for (let i = 0; i < this.subjectOneList.length; i++) {
            if (this.subjectOneList[i].id === value) {
                this.subjectTwoList = this.subjectOneList[i].children
                this.courseInfo.subjectId = ''
            }
        }
    },
    //查询一级分类
    getOneSubject(){
        subject.getSubjectList()
            .then(response =>{
                this.subjectOneList = response.data.list
            })
    },
    //查询所有讲师
    getTeacherList(){
        course.getTeacherList()
            .then(response =>{
                this.teacherList = response.data.items
            })
    },
    //保存信息
    saveOrUpdate(){
        //判断添加还是修改
        if (!this.courseInfo.id)
        {
            this.addCourse()
        }
        else
        {
            this.updateCourse()
        }
    },
    //添加课程信息
    addCourse(){
        course.addCourseInfo(this.courseInfo)
            .then(response =>{
                //提示信息
                this.$message({
                    type: 'success',
                    message:"添加课程信息成功"
                })
                //跳转到下一页
                this.$router.push({path:'/course/chapter/'+response.data.courseId})
            })
    },
    //修改课程信息
    updateCourse(){
        course.updateCourseInfo(this.courseInfo)
            .then(response => {
                //提示信息
                this.$message({
                    type: 'success',
                    message:"修改课程信息成功"
                })
                //跳转到下一页
                this.$router.push({path:'/course/chapter/'+this.courseId})
            })
    }
  }
}
</script>
<style scoped>
.tinymce-container {
  line-height: 29px;
}
</style>